[Lustre-discuss] Is OFED 'kernel-ib' required for o2ib on RHEL5?

[Brian J. Murrell]

On Tue, 2010-03-23 at 11:59 -0400, Lawrence Sorrillo wrote: 
> 
> The caveat here is that the RHEL5 kernel-version used should be one 
> supported by SUN?

There are two kernels.  One which we distribute, patched, for the
servers.  It has OFED and the lustre-modules RPM has an o2iblnd.ko built
against it.

The other kernel is the patchless kernel, available from RH.  It should
be the one we declared as officially supported by the release and will
have the same version as the patched kernel we distribute per the above.
The o2iblnd in the lustre-client-modules will be built against that.

It is also possible through something called "weak-modules" to use the
modules in one given lustre-client-modules package with another kernel
that has a matching kABI, but utilizing that feature is left as an
exercise for the reader (for the time being).

> If this is so then to get a lustre client service one only has to 
> install the corresponding
> 
> lustre-client-modules-xxxx
> lustre-client
> 
> Then lustre with IB in RHEL5 should work?

That's correct.  For RHEL5 on 1.8.2, and likely more future releases
than not.  It is our goal to utilize the vendor's integrated stack when
it makes sense to do so.  We hope it makes sense most, if not all of the
time now that OFED seems to be stabilizing and Linux vendors are
including up-to-date releases of it more frequently.

> The module, o2iblndm, does not seem to come from a stock RHEL5 build.

No.  That's the Lustre module that utilizes OFED.

> It 
> comes from lustre-client-modules-xxxx?

Yes.  And lustre-modules, for the servers.

b.

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